The copper-zinc separation process is one of the most challenging flotation separation processes, mainly because the first step must be batch flotation of the two most easily floatable minerals and separation of the two minerals in the differential flotation stage. mineral.

In general, copper and lead minerals are usually the target bulk flotation minerals since both are susceptible to flotation. Thus, standard copper-lead-zinc flotation practice involves initial flotation of copper-lead bulk concentrate, followed by two parallel cyclic stages of copper-lead separation, and zinc flotation from bulk flotation tailings.

For lead-zinc ore processing, zinc sulphate and partial disulfide sphalerite and pyrite inhibitors are usually added to the mill separately. The copper-lead bulk concentrate is then recovered using a xanthate, dithiophosphate and flotation reagent mixture. The choice of collector in the bulk flotation step must take into account the impact on the subsequent copper-lead separation stage where stronger collectors may not be well tolerated. In general, lead minerals (usually galena) float readily and the selection of an optimal copper collector will provide good lead recovery. In some cases, maximizing bulk copper recovery may require the use of thiocarbamate and thiocarbamate collectors as well as dithiophosphate and xanthate chemicals in bulk flotation.
Which flotation scheme to use in differential copper-lead bulk concentrate separation usually depends on which mineral is of greater mass in the bulk concentrate. Whichever minerals make up the lower bulk concentrate quality will float out of other minerals that are inhibited due to flotation selectivity reasons. When deciding which copper or lead mineral to float from another, other factors related to the processing characteristics of a particular copper and lead mineral must be considered, such as relative mineral flotation kinetics.

Regardless, the subsequent copper-lead separation flotation step is usually alkaline and in most cases the copper minerals are floated after the galena sinks. Use sodium dichromate, sodium sulfite, polysaccharides (starch, dextrin) and even at pH. In the case of flotation of galena and depression of copper minerals, it can be achieved by using sodium sulfide, dithionite, lime, cyanide, zinc cyanide and the choice of flotation and frother is an important, even a key consideration. Mineralogy, circuit configuration and process step goals must be considered when selecting flotation reagents.